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14 Articles in Volume 18, Issue #7
A 2018 Update: The Federal Pain Research Strategy
A Commentary on Medical Cannabis
Are Abuse-Deterrent Opioids Appropriate for Your Pain Patient?
Behind the AHRQ Report
Challenges Facing Abuse-Deterrent Formulations
Demystifying Opioid Abuse-Deterrent Technologies
Editorial: Our Clinical Pain Neighborhood
Independent Pain Practice: A Case Example
Inside Performing Arts Medicine
Letters to the Editor: ACT Therapy; Compounded Topicals
Nerve Growth Factor and Targeting Chronic Pain
Pain Control for Athletes: What Works?
Quality Training: One Center’s Experience with Pain Assessment
The Importance of Developing Professional Relationships in Pain Practice

A Commentary on Medical Cannabis

What clinicians need to know about its role in pain management.

The Stakes

Marijuana has been around for thousands of years and has been reported to have medical benefits, ranging from pain to curing cancer.1,2 The state of Colorado established its medical marijuana program in 2001 designed initially for use in compassionate care and, to date, 31 states have implemented similar programs. Since 2009, dispensaries have multiplied to the point that they outnumber the combined Starbucks and McDonald’s across the state.

As additional states and the healthcare community at large continue to consider the use and medical benefits of cannabis in treating chronic pain, it is crucial that, as a medication, cannabis meet the rigor of scientific study just as every other plant-based medication has to date (eg, aspirin, some heart medications, and a variety of chemotherapy agents). It is equally important that pharmacy grade products be free of contaminants, which in generic—or dispensary form—may include heavy metals, pesticides, fungicides, rodenticides, and other particulates.

Cannabinoids are purified components from the plant that are isolated in a controlled setting. Synthetic cannabinoids are also purified compounds manufactured and purified in a laboratory. These have been used for nausea and vomiting associated with chemotherapy and they have been around for the past three decades.

Cannabis oil and ediblesCannabis may play a role in pain management (Credit: 123RF)

The Literature

In 2015, Whiting, et al., published a comprehensive systematic review, outlining both the benefits and adverse events associated with cannabis use.3 The authors concluded that, “there was moderate-quality evidence for the use of cannabinoids in chronic pain,” noting that most studies had a high risk of bias and that the conditions studied were primarily neuropathic and cancer pain, with products unavailable in the US or with synthetic tetrahydrocannabinol (THC), the principal psychoactive constituent of cannabis shown to have analgesic effects, rather than the more widely available dispensary cannabis.

In early 2017, the National Academies of Science, Engineering, and Medicine leaned heavily on conclusions made by Whiting, reaching the same conclusion: “in adults with chronic pain, patients who were treated with cannabis or cannabinoids are more likely to experience a clinically significant reduction in pain symptoms.”1 The Academies further noted that only a handful of studies evaluated the benefit of dispensary cannabis in the US and that little is known about dosing, routes of administration, or side effects.

That same year, Nugent, et al., authored a paper that further clarified that the medical literature may support the use of cannabinoids in neuropathic and cancer pain, and there is little evidence to show any benefit in common pain conditions.4 The authors also noted no evidence of benefit with dispensary cannabis.

More recently, in February 2018, The College of Family Physicians of Canada released a simplified guideline for prescribing medical cannabinoids in primary care to 30,000 physicians in their country.5 After performing a thorough medical literature review, the College recommended strongly against the use of medical cannabinoids for acute pain, headache, osteoarthritis, and back pain.

The College recommended that if prescribing cannabis for pain, a clinician utilize a pharmaceutically developed product for neuropathic or cancer pain. Unfortunately, in the US’s fragmented medical system, “off label” use of a pharmacy grade cannabinoid is typically not permitted and expensive, natural, pharmacy grade cannabinoids such as Sativex (GW Pharmaceuticals) are not currently available.

There currently is no accepted data to support the use of dispensary cannabis for clinical usage to treat other painful conditions, such as fibromyalgia and rheumatoid arthritis.


The Challenges 

Colorado’s Program Is Not the Answer

Using Colorado as a model, it is important to be aware that Denver Public Health has routinely recalled contaminated marijuana products for the past 3 years.6 Moreover, cannabis use has not curbed the state’s opioid epidemic. In fact, in 2017, the state reported a record number of opioid overdose deaths in Colorado.7,8 Since legalization, not only has there been a continued increase in opioid overdose deaths, but also, there has been a resurgence of deaths associated with cocaine and methamphetamine. This situation has occurred despite an increase in public awareness of the opioid epidemic, wherein, like other states; healthcare providers are less inclined to prescribe opioids for a variety of reasons and patients are more reluctant to want an opioid prescription. The state has further witnessed an increase in utilization of its Prescription Drug Monitoring Program, and widespread use of naloxone, the reversal agent for opioid overdose.

In fact, medical marijuana laws appear to have contributed to increased prevalence of illicit cannabis use and cannabis use disorder.8 This disorder is one of the most common diagnoses for adolescent substance use treatment in Colorado and there are well-documented mental health effects of the drug, including anxiety, depression, and psychosis.4 Not everyone who uses cannabis will experience such adverse events, but with increased use, it is likely that the number of individuals affected will increase. Further, cannabis is the most common substance found on toxicology in completed suicide in the state of Colorado in those aged 10- to 19-years-old, and across all age groups, the prevalence of marijuana in suicide is skyrocketing.6-7

Finding Adequate Concentrations

The “God’s plant” cannabis provides about 0.5 to 3% THC concentration. Concentrated products of today are more likely to be in the range of 15 to 90% THC.

Cannabidiol or CBD, the non-psychoactive component of the cannabis plant, has shown some promise as a medical treatment, particularly for the management of pediatric seizure (FDA recently approved Epidiolex, GW Pharmaceuticals). The University of Alabama-Birmingham is just one center studying this compound, and data thus far is positive for treating this particular disease state.

However, of CBD products, many of which are available online, only 31% were accurately labeled in terms of CBD content and up to 21% also carried THC.9 In the regulated markets of California and Washington, a similar study showed that only 17% of CBD products were accurately labeled as to THC content and only 59% had detectable levels of CBD.10 These data reinforce the imperative of testing for purity and potency of all available cannabis-based products.

Overall, medical use of cannabis, in general, may offer benefit for those suffering from select pain disorders. Just like any medicine, it should meet the muster of scientific rigor and research. Colorado’s program may be used as a model of what works—but perhaps more importantly, what does not work when implementing dispensaries that make this product available to a broad range of individuals. Dosing guidelines need to be widely available and generally accepted. Products which are free of contaminants, tested consistently, and purified may benefit patients. However, science, not public opinion or anecdotes, should determine what is best for patient health and public safety.

See also Dr. Michael Schatman's take on medical cannabis during PAINWeek 2018.


Additional Facts about Medical Cannabis: 

Reported by Kerri Wachter

Tetrahydrocannabinol (THC) and cannabidiol (CBD), along with other cannabinoids, terpenes, and flavonoid compounds, are thought to exhibit synergistic effects that promote pain relief, with THC being the most psychoactive cannabinoid found in cannabis with potential for reducing nausea and increasing appetite. CBD, which does not provide the euphoria associated with THC, has been associated with reduced pain and inflammation.1-3

The substance is available in herbal (marijuana), tincture, oil, and edible forms. It can be smoked, vaporized, ingested in edible or other oral forms, taken sublingually, or applied topically. Research on the efficacy of different routes of administration for pain is sparse. Some studies have suggested that smoking cannabis produces rapid effects, while oral forms take longer to work but may last longer.4

Medical cannabis is legal in 31 states, many of which require patient registry or identification cards for purchase and use in treating specific diagnosed medical conditions. These conditions differ by state and continue to change. In 24 of these states, some type of product testing is required. Testing varies by state and may be limited to contamination tests or may include quantification of CBD and THC levels. California, for example, requires dispensaries to sell only marijuana that has been tested for pesticides, contaminants, microbial impurities, and, more recently, plant potency.5

At the federal level, marijuana is classified as a Schedule I substance and there are no recognized medical uses. FDA approval, has, so far, been limited to synthetic or pharmaceutical-grade components.


Last updated on: May 14, 2019
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What Pain Specialists Need to Know About Medicinal Cannabis
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